Kasdan, 23, also wrote and produced the comedy thriller, the story of Daryl Zero (Pullman), a brilliant private detective who barely functions in real life. Afraid to leave his secret L.A. apartment or have any friends, Zero's only contact with the outside world is Steve Arlo (Stiller), a young attorney who works as his front man.

Zero and Arlo get more than they bargained for, though, when they take on the case of a Portland timber tycoon (O'Neal) who has lost his key to his safety deposit box.

Kasdan, who appeared in cameos in his father's films "The Big Chill," "Silverado" and "The Accidental Tourist," has previously written and directed four plays, most recently "The Behavioral Patterns of Funnyman Tyler Hudson," which ran two years ago at the Hollywood Playhouse.

Just before the Los Angeles premiere of "Zero Effect," Kasdan sat down in a conference room at Castle Rock to talk about his love of movies, making "Zero Effect" and, of course, following in the footsteps of his Oscar-nominated father.

Question: Were you inspired to become a director because you spent so much time on sets growing up?

Answer: When I was a really little kid I thought, "This is what I want to do." I knew what I wanted to do when I was 5 or 6. Of course, when you are a little kid, it's more of an abstract kind of notion. The older I got and the more I learned, I sort of stayed with one clear goal.

You know, I think you have to really sort of [love movies] to care enough about it to where you want to pour all of your time into it--you have to in some visceral way really love movies. I love going to movies.

I love all different kinds of movies and all different kinds of genres. You discover a set of movies or a filmmaker or a time period which sort of lights your Bunsen burner and makes you want to work.

When I was 14 or 13, I discovered these volumes of character dramas from the early to mid-'70s, all of these directors who were doing amazing stuff like Sydney Pollack, Alan Pakula, William Friedkin and Francis Coppola--movies that are really significant to you, you return to. A lot of my dad's movies have affected me.

Q: Did you ever attend film school?

A: I went to a couple of colleges as an undergraduate for a very, very short time and dropped out of both. I was taking some playwriting stuff, but mainly I was studying linguistics. I stopped going because I was spending all my time writing stuff and wasting everybody's time.

I started writing stage plays when I was in high school. I would rent these theaters and put them up.

Until I started writing plays and I convinced myself I was good at it, most of my life experience has been that I am not good at things. When I found something that I felt I could do, it was a tremendous relief because I was the last kid picked for every kind of team in school. You find something that you have got muscles for you didn't expect and it's like "Whew!"

Q: How did you make the leap to screenwriting?

A: A few years ago, I decided I was going to start writing screenplays. I love stage plays and I hope to keep doing that. [Screenwriting] was really sort of a separate and maybe my primary goal.

Q: I thought Daryl Zero and Steve Arlo were sort of contemporary versions of Sherlock Holmes and John Watson.

A: I love those stories and am deeply influenced by those stories and by the genre of master detective. There is a great tradition of these master detectives with highly developed minds who have some sort of a manner of deficiency. They say if you are missing a sense, the others become highly attuned and developed. I wanted to write about the ways that people can really be good at some things and really bad at other things. There is a reality to his dilemma and his problems and a reality I certainly can relate to!

Daryl is only really comfortable when he is not assuming his own character.

Q: You met Pullman while he was working with your father on "The Accidental Tourist" 10 years ago. Did you write Daryl with him in mind?

A: When I started writing it, I didn't know I was going to try to make a movie with it. I wanted to write a script and work on it and see what I could do with it. As soon as I started thinking about turning this story into a movie, Bill was the clear, obvious choice to me.

We had been as friendly as a 13-year-old and someone who is a married adult with children can be. Bill is an exceedingly decent guy and he's really wonderful with kids and doesn't relate to a 13-year-old as a 13-year-old. We had talked about working on something else a couple of years ago. As soon as I started putting faces to these parts, I could see that Daryl Zero fell into our sort of mutual interest zone.